Complex Equation: Drawing Set of Points |z+3i|=4

In summary, the equation |z + 3i| = 4 represents all the complex numbers that are within 4 units of -3i, which can also be written as |z - (-3i)| = 4. This suggests a graph of a circle.
  • #1
lockedup
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Homework Statement


Draw the set of points in the complex plane satisfying the equation |z + 3i| = 4


Homework Equations





The Attempt at a Solution

I don't know what z is supposed to be. In class, we've been using z to stand for a complex number (x + yi). Am I supposed to substitute that into the equation? Or, am I supposed to treat z like any real number and find the absolute value?
 
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  • #2
lockedup said:

Homework Statement


Draw the set of points in the complex plane satisfying the equation |z + 3i| = 4


Homework Equations





The Attempt at a Solution

I don't know what z is supposed to be. In class, we've been using z to stand for a complex number (x + yi). Am I supposed to substitute that into the equation? Or, am I supposed to treat z like any real number and find the absolute value?

Yes, z is a complex number. The equation you give represents all the complex numbers that are within 4 units of -3i. You could also write the equation as |z - (-3i)| = 4 to emphasize that we're talking about distance. The fact that we're talking about the points that are a fixed distance from a fixed point should suggest a particular kind of shape.
 
  • #3
Thank you, it's coming back to me now. It the graph of a circle. :*)
 

Related to Complex Equation: Drawing Set of Points |z+3i|=4

1. What does the equation "z+3i=4" represent?

The equation represents a complex number, z, added to the imaginary number 3i, which equals the real number 4.

2. What does the equation "z+3i=4" look like on a graph?

The equation represents a circle on a graph, with a radius of 4 units and a center at (-3,0).

3. How do you draw a set of points for the equation "z+3i=4"?

To draw a set of points for the equation, you can plot all the points that lie on the circle with a radius of 4 and a center at (-3,0).

4. Can a complex equation have more than one solution?

Yes, a complex equation can have more than one solution. In the case of "z+3i=4", there are infinitely many points that satisfy the equation and lie on the circle.

5. How can complex equations be useful in real-life applications?

Complex equations are used in a variety of fields, such as engineering, physics, and economics, to model and solve problems involving quantities with both real and imaginary components. For example, in electrical engineering, complex equations are used to analyze circuits with both resistance and reactance. In physics, they are used to describe the behavior of waves and oscillations. And in economics, they are used in calculating interest rates and exchange rates.

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